Compared: Voigtlander Ultron 21mm f/1.8 vs Leica 21mm f/3.4 Super-Elmar-M ASPH (M240, Wyman Canyon Lower Cabin Interior)
Voigtlander Ultron 21m f/1.8 lens is about $1149 for Leica M.
Includes HD and UltraHD aperture series and the Voigtlander Color-Skopar 21mm f/4 is included as well.
Chris L writes:
As a Voigtländer aficionado, I thought I should know if such a beast
existed in mounts other than Leica M.
Neither BHphoto nor Cosina/Voigt themselves mention it in Canon EF or
Nikon F mounts.
DIGLLOYD: the Voigtlander Ultron 21mm f/1.8 is an M-mount lens (Leica M rangefinder) with a short backfocus ; it is impossible to use it on a DSLR.
It could be used via an adapter on mirrorless cameras like the Sony A7s/A7/A7R, but ray angle issues would severely degrade its peripheral quality at wider apertures. Stopped down to f/8 - f/11 it might perform well however. See the coverage of various wide angle Leica M lenses on Sony A7/A7R in Guide to Leica.